Cereal Chem 58:460 - 463.  |  VIEW ARTICLE
Trypsin Inhibitor from Wheat Endosperm: Purification and Characterization.

S. Boisen and R. Djurtoft. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

A trypsin inhibitor was purified from wheat flour by extraction with 0.1M sodium acetate buffer (pH 5.0), fractionation with ammonium sulfate, heat treatment, anion and cation exchange chromatography on diethylaminoethyl-Sephadex and SP-Sephadex, respectively, and gel filtration in Ultrogel AcA 54. The final preparation was homogeneous by electrophoretic analyses. The isolated inhibitor was a basic protein with a pI of about 9.0. Molecular weights of 12,500 and 12,300 were calculated from sodium dodecyl sulfate polyacrylamide gel electrophoresis and from amino acid composition, respectively. Inhibition of bovine trypsin was linear and stoichiometric up to 90% inhibition with benzoyl-L-arginine-p-nitroanilide as substrate and to 70% with casein as substrate. The preparation was also found to have a weak inhibitory action on bovine chymotrypsin. This action was not stoichiometric. The inhibitor was very stable to pepsin at pH 2.0 and to heat at 100 C. The purified inhibitor is immunochemically different from other known cereal trypsin inhibitors in wheat, barley, and rye.